Azobenzene

Azobenzene
Names
	IUPAC name (E)-Diphenyldiazene
	Other names Azobenzene
Identifiers
CAS Number	103-33-3 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	742610
ChEBI	CHEBI:58996 ;
ChEMBL	ChEMBL58835 ;
ChemSpider	2185 ;
ECHA InfoCard	100.002.820
EC Number	203-102-5;
Gmelin Reference	83610
KEGG	C19334 ;
PubChem CID	2272;
RTECS number	CN1400000;
UNII	F0U1H6UG5C ;
CompTox Dashboard (EPA)	DTXSID8020123 ;
	InChI InChI=1S/C12H10N2/c1-3-7-11(8-4-1)13-14-12-9-5-2-6-10-12/h1-10H/b14-13+ Key: DMLAVOWQYNRWNQ-BUHFOSPRSA-N ; InChI=1/C12H10N2/c1-3-7-11(8-4-1)13-14-12-9-5-2-6-10-12/h1-10H/b14-13+ Key: DMLAVOWQYNRWNQ-BUHFOSPRBP;
	SMILES N(=N/c1ccccc1)\c2ccccc2;
Properties
Chemical formula	C12H10N2
Molar mass	182.226 g·mol−1
Appearance	orange-red crystals
Density	1.203 g/cm3
Melting point	67.88 °C (trans), 71.6 °C (cis)
Boiling point	300 °C (572 °F; 573 K)
Solubility in water	6.4 mg/L (25 °C)
Acidity (pKa)	-2.95
Magnetic susceptibility (χ)	-106.8·10−6 cm3/mol
Refractive index (nD)	1.6266 (589 nm, 78 °C)
Structure
Molecular shape	sp2 at N
Dipole moment	0 D (trans isomer)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	toxic
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H332, H341, H350, H373, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P314, P330, P391, P405, P501
Flash point	476 °C (889 °F; 749 K)
Related compounds
Related compounds	Nitrosobenzene aniline
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Azobenzene is a photoswitchable chemical compound composed of two phenyl rings linked by a N=N double bond. It is the simplest example of an aryl azo compound. The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of similar compounds. These azo compounds are considered as derivatives of diazene (diimide),^[4] and are sometimes referred to as 'diazenes'. The diazenes absorb light strongly and are common dyes.^[5] Different classes of azo dyes exist, most notably the ones substituted with heteroaryl rings.^[6]

^ ^a ^b ^c ^d ^e Haynes, p. 3.32
^ Hoefnagel, M. A.; Van Veen, A.; Wepster, B. M. (1969). "Protonation of azo-compounds. Part II: The structure of the conjugate acid of trans-azobenzene". Recl. Trav. Chim. Pays-Bas. 88 (5): 562–572. doi:10.1002/recl.19690880507.
^ Haynes, p. 3.579
^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2009) "azo compounds". doi:10.1351/goldbook.A00560
^ Saul Patai, ed. (1975). Hydrazo, Azo and Azoxy Groups. PATAI'S Chemistry of Functional Groups. Vol. 1. John Wiley & Sons. doi:10.1002/0470023414. ISBN 9780470023419.
^ Crespi, Stefano; Simeth, Nadja A.; König, Burkhard (March 2019). "Heteroaryl azo dyes as molecular photoswitches". Nature Reviews Chemistry. 3 (3): 133–146. doi:10.1038/s41570-019-0074-6. ISSN 2397-3358.

[crc-1] Haynes, p. 3.32

[2] Hoefnagel, M. A.; Van Veen, A.; Wepster, B. M. (1969). "Protonation of azo-compounds. Part II: The structure of the conjugate acid of trans-azobenzene". Recl. Trav. Chim. Pays-Bas. 88 (5): 562–572. doi:10.1002/recl.19690880507.

[3] Haynes, p. 3.579

[Gold-4] IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2009) "azo compounds". doi:10.1351/goldbook.A00560

[5] Saul Patai, ed. (1975). Hydrazo, Azo and Azoxy Groups. PATAI'S Chemistry of Functional Groups. Vol. 1. John Wiley & Sons. doi:10.1002/0470023414. ISBN 9780470023419.

[6] Crespi, Stefano; Simeth, Nadja A.; König, Burkhard (March 2019). "Heteroaryl azo dyes as molecular photoswitches". Nature Reviews Chemistry. 3 (3): 133–146. doi:10.1038/s41570-019-0074-6. ISSN 2397-3358.

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